/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
 * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
 *
 * The original version of this source code and documentation
 * is copyrighted and owned by Taligent, Inc., a wholly-owned
 * subsidiary of IBM. These materials are provided under terms
 * of a License Agreement between Taligent and Sun. This technology
 * is protected by multiple US and International patents.
 *
 * This notice and attribution to Taligent may not be removed.
 * Taligent is a registered trademark of Taligent, Inc.
 */

package java.util;

import java.io.InputStream;
import java.io.Reader;
import java.io.IOException;
import sun.util.ResourceBundleEnumeration;

/**
 * <code>PropertyResourceBundle</code> is a concrete subclass of <code>ResourceBundle</code> that
 * manages resources for a locale using a set of static strings from a property file. See {@link
 * ResourceBundle ResourceBundle} for more information about resource bundles.
 *
 * <p> Unlike other types of resource bundle, you don't subclass <code>PropertyResourceBundle</code>.
 *  Instead, you supply properties files containing the resource data.
 * <code>ResourceBundle.getBundle</code> will automatically look for the appropriate properties file
 * and create a <code>PropertyResourceBundle</code> that refers to it. See {@link
 * ResourceBundle#getBundle(java.lang.String, java.util.Locale, java.lang.ClassLoader)
 * ResourceBundle.getBundle} for a complete description of the search and instantiation strategy.
 *
 * <p> The following <a name="sample">example</a> shows a member of a resource bundle family with
 * the base name "MyResources". The text defines the bundle "MyResources_de", the German member of
 * the bundle family. This member is based on <code>PropertyResourceBundle</code>, and the text
 * therefore is the content of the file "MyResources_de.properties" (a related <a
 * href="ListResourceBundle.html#sample">example</a> shows how you can add bundles to this family
 * that are implemented as subclasses of <code>ListResourceBundle</code>). The keys in this example
 * are of the form "s1" etc. The actual keys are entirely up to your choice, so long as they are the
 * same as the keys you use in your program to retrieve the objects from the bundle. Keys are
 * case-sensitive. <blockquote>
 * <pre>
 * # MessageFormat pattern
 * s1=Die Platte \"{1}\" enth&auml;lt {0}.
 *
 * # location of {0} in pattern
 * s2=1
 *
 * # sample disk name
 * s3=Meine Platte
 *
 * # first ChoiceFormat choice
 * s4=keine Dateien
 *
 * # second ChoiceFormat choice
 * s5=eine Datei
 *
 * # third ChoiceFormat choice
 * s6={0,number} Dateien
 *
 * # sample date
 * s7=3. M&auml;rz 1996
 * </pre>
 * </blockquote>
 *
 * <p> The implementation of a {@code PropertyResourceBundle} subclass must be thread-safe if it's
 * simultaneously used by multiple threads. The default implementations of the non-abstract methods
 * in this class are thread-safe.
 *
 * <p> <strong>Note:</strong> PropertyResourceBundle can be constructed either from an InputStream
 * or a Reader, which represents a property file. Constructing a PropertyResourceBundle instance
 * from an InputStream requires that the input stream be encoded in ISO-8859-1.  In that case,
 * characters that cannot be represented in ISO-8859-1 encoding must be represented by Unicode
 * Escapes as defined in section 3.3 of <cite>The Java&trade; Language Specification</cite> whereas
 * the other constructor which takes a Reader does not have that limitation.
 *
 * @see ResourceBundle
 * @see ListResourceBundle
 * @see Properties
 * @since JDK1.1
 */
public class PropertyResourceBundle extends ResourceBundle {

  /**
   * Creates a property resource bundle from an {@link java.io.InputStream
   * InputStream}.  The property file read with this constructor
   * must be encoded in ISO-8859-1.
   *
   * @param stream an InputStream that represents a property file to read from.
   * @throws IOException if an I/O error occurs
   * @throws NullPointerException if <code>stream</code> is null
   * @throws IllegalArgumentException if {@code stream} contains a malformed Unicode escape
   * sequence.
   */
  @SuppressWarnings({"unchecked", "rawtypes"})
  public PropertyResourceBundle(InputStream stream) throws IOException {
    Properties properties = new Properties();
    properties.load(stream);
    lookup = new HashMap(properties);
  }

  /**
   * Creates a property resource bundle from a {@link java.io.Reader
   * Reader}.  Unlike the constructor
   * {@link #PropertyResourceBundle(java.io.InputStream) PropertyResourceBundle(InputStream)},
   * there is no limitation as to the encoding of the input property file.
   *
   * @param reader a Reader that represents a property file to read from.
   * @throws IOException if an I/O error occurs
   * @throws NullPointerException if <code>reader</code> is null
   * @throws IllegalArgumentException if a malformed Unicode escape sequence appears from {@code
   * reader}.
   * @since 1.6
   */
  @SuppressWarnings({"unchecked", "rawtypes"})
  public PropertyResourceBundle(Reader reader) throws IOException {
    Properties properties = new Properties();
    properties.load(reader);
    lookup = new HashMap(properties);
  }

  // Implements java.util.ResourceBundle.handleGetObject; inherits javadoc specification.
  public Object handleGetObject(String key) {
    if (key == null) {
      throw new NullPointerException();
    }
    return lookup.get(key);
  }

  /**
   * Returns an <code>Enumeration</code> of the keys contained in
   * this <code>ResourceBundle</code> and its parent bundles.
   *
   * @return an <code>Enumeration</code> of the keys contained in this <code>ResourceBundle</code>
   * and its parent bundles.
   * @see #keySet()
   */
  public Enumeration<String> getKeys() {
    ResourceBundle parent = this.parent;
    return new ResourceBundleEnumeration(lookup.keySet(),
        (parent != null) ? parent.getKeys() : null);
  }

  /**
   * Returns a <code>Set</code> of the keys contained
   * <em>only</em> in this <code>ResourceBundle</code>.
   *
   * @return a <code>Set</code> of the keys contained only in this <code>ResourceBundle</code>
   * @see #keySet()
   * @since 1.6
   */
  protected Set<String> handleKeySet() {
    return lookup.keySet();
  }

  // ==================privates====================

  private Map<String, Object> lookup;
}
